Typedef

typedef objects define a type using NewType similar to type alias.

Static type checker will treat the new type as if it were a subclass of the original type. This is useful in helping catch logical errors:

In the following example Color is a NewType of int Color = typing.NewType('Color', int)

Example:

from ooo.dyn.util.color import Color
c1 = Color(234)
c2 = Color(6)
assert isinstance(c1, int)
result = c1 + c2
assert result == 240

Typedef’s in ooo are the same across all namespaces and do not have any dynamic generation.

>>> from ooo.lo.util.color import Color as LoColor
>>> from ooo.dyn.util.color import Color as DynColor
>>> from ooo.csslo.util import Color as CssLoColor
>>> from ooo.cssdyn.util import Color as CssDynColor
>>> LoColor is DynColor
True
>>> LoColor is CssLoColor
True
>>> LoColor is CssDynColor
True

Note

Checks for NewType are enforced only by the static type checker. At runtime the statement Color = NewType(‘Color’, int) will make Color a function that immediately returns whatever parameter you pass it. That means the expression Color(some_value) does not create a new class or introduce any overhead beyond that of a regular function call.